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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

27394 results found.

  1. GRB 030328: Optical observations
  2. GRB030324 optical observation
  3. GRB030131, BVRcIc field photometry
  4. Possible GRB030323 localized by INTEGRAL
  5. GRB030323: Detection on 2003/03/24
  6. IPN triangulation of GRB030326 (single small error box)
  7. IPN triangulation of GRB030325 (two small error boxes)
  8. GRB030323: V, R, I photometry
  9. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  10. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  11. VLT/FORS2 spectra of GRB 030323
  12. GRB030323, optical observations
  13. GRB030324, BVRcIc field photometry
  14. GRB030323, BVRcIc field calibration
  15. IPN triangulation of GRB030320 (small error box)
  16. Possible GRB 030320 localized by INTEGRAL
  17. IPN triangulation of GRB030306 (single small error box - REVISED)
  18. IPN triangulation of GRB030306 (single small error box)
  19. IPN triangulation of GRB030306 (two small error boxes)
  20. GRB030226, BVRc observations
  21. Chandra detection of the X-ray afterglow of GRB 030226
  22. GRB030227: Kiso optical upper limit
  23. GRB030227, BVRcIc field photometry
  24. GRB030226, BVRcIc field calibration
  25. GRB 030228, optical observations
  26. GRB 030227: Confirmed Optical Afterglow (S1-A)
  27. GRB 030227: fading of candidate optical afterglow 'S1-A'
  28. GRB030227:Optical observations
  29. GRB 030227, possible optical counterpart of XMM-Newton source
  30. GRB030227 - faint tentative OT candidate
  31. GRB 030226, optical observations
  32. XMM-Newton observation of GRB030227
  33. GRB030227: Kiso optical observations
  34. GRB 030227: Kyoto optical observation
  35. GRB 030226, optical light curve
  36. GRB030227 localized by INTEGRAL
  37. GRB 030226 : Predicted light curve
  38. GRB030226: ESI spectroscopy
  39. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  40. GRB 030226 simultaneous optical observations
  41. GRB 030226, optical observations
  42. GRB030226: Optical decay index
  43. GRB 030226 Optical Spectra and R,I,z' Imaging
  44. GRB: Non-Referencing of GCN Circulars.
  45. IPN triangulation of GRB030217 (small error box)
  46. GRB 030131: marginal optical detection
  47. GRB 030204: Optical Observations
  48. GRB030204 field photometry
  49. GRB020819: Kiso R and I band observations
  50. GRB030131: Candidate Optical Afterglow
  51. IPN triangulation of GRB030204 (small error box)
  52. GRB 030131, optical observations
  53. GRB 030131: afterglow candidate
  54. GRB 030115, late-time optical observations
  55. GRB030131: corrected INTEGRAL position
  56. GRB 020819: Host galaxy at Radio Position
  57. IPN triangulation of GRB030131
  58. GRB 030131 optical observations
  59. GRB 030131 optical observations
  60. A long GRB detected by INTEGRAL
  61. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  62. GRB 030115, simultaneous observations by BOOTES-1
  63. GRB 030115: IR observations with IRSF/SIRIUS
  64. IPN triangulation of GRB030115C (large error box)
  65. GRB030115, afterglow candidate
  66. GRB 021211: R-band observations at late-time
  67. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  68. GRB 030115 : Possible IR counterpart
  69. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  70. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  71. GRB 030115: APO Optical Observations
  72. Information about where HETE will be pointing
  73. VLT spectroscopy of the probable host of GRB 021211
  74. IPN triangulation of GRB030101 (two large error boxes)
  75. GRB 021211: Probable Host and Underlying Supernova
  76. GRB 021112: Evidence for Another Dark Optical Afterglow
  77. GRB 021219: OSN optical observations
  78. GRB021219, optical observations
  79. GRB021219, optical observation by MASTER
  80. VLT spectra of GRB 021211 revisited
  81. GRB021219: a long GRB localized by INTEGRAL
  82. GRB021211: APO optical observations
  83. XRF 020903 : HST observations
  84. GRB 021201: Optical Observations
  85. GRB 021211: CTIO observations
  86. GRB021211, BVRI field photometry
  87. GRB021211: Optical observations in CrAO
  88. GRB 021211, optical observations
  89. GRB021211: Kiso Observations
  90. GRB 021201, optical observations
  91. GRB021211: Optical observations
  92. GRB 021201 (short/hard), NOT observations
  93. SUB-MM SEARCH FOR GRB 021211
  94. Chandra observation of the IPN error box of GRB021201 (short/hard)
  95. GRB 021211, R- and I-band observations
  96. GRB021211 - Upper limits from recent and historical observations
  97. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  98. IPN triangulation of GRB021206 (small error box)
  99. IPN triangulation of GRB021205 (large error box)
  100. GRB021201, BVRcIc field photometry

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